1. Field of the Invention
The invention relates to a sling element for coupling sling gear, such as a shackle, hook or ring, or a lifting means, such as a belt, a rope, a chain or a strap, to a goods item to be transported, wherein the sling element has a fastening section into which an oblong-shaped opening is formed which leads from the upper side of the fastening section to a contact area formed on the underside of the fastening section. The invention also relates to a combination consisting of a sling element of that kind and a fastening means, wherein the fastening means can comprise a tensioning element and an adapter piece.
2. Description of Related Art
Sling elements of the kind in question here usually have a fastening section, with which they can be directly fastened to the goods item to be transported, and a sling element, to which the respective lifting means, such as a belt, rope, chain or strap, by means of knots or loops can be either directly connected or, due to practical and safety-related considerations, can be connected via sling gear serving as an intermediate element, such as a shackle, a hook or ring. At the same time, openings are formed into the fastening sections, through which a fastening means, which is typically a screw or a bolt, can be guided into a corresponding opening on the respective flange of the goods item to be transported. In order to make mounting and alignment of the sling element easier, the openings concerned are generally formed as elongated holes, so that the exact angular position of the respective sling element can be adjusted again before final bracing of the respective fastening element.
Such sling gear is, for example, used for lifting and aligning tall steel, separately prefabricated tower elements of wind power plants or comparably sized pipes of pipelines or the like. The diameter of such, in each case tubular, elements is generally considerably less than their length. The elements are therefore transported to the respective site lying flat.
In the case of tower elements, they then at the site not only have to lifted from the heavy transporter, wagon or ship used to transport them and swung into their final position, but they also, additionally, have to be turned from a horizontal alignment into a vertical alignment, so that they can be placed onto a base or a tower element which has already been erected.
For lifting and aligning, typically in each case at least two sling elements are fastened to the face sides of the end flanges of the tubular elements, so that the one sling element is mounted, for example, at 10 o'clock and the second element at 2 o'clock.
As a result of this arrangement, the line of effect of the lifting forces, which act on the fastening means used to fasten the respective sling element when lifting the goods item to be conveyed, is aligned at an acute angle to the effect of gravity. Due to the fact that the fastening means in each case sits in an oblong opening of the assigned fastening section of the sling element, in the event that the respective tensioning means is not tightened with sufficient force, the sling element can, therefore, slip under the load. After overcoming the friction prevailing between the sling element and the respective flange, this slipping occurs abruptly many times, so that a dangerous, sudden overloading of the fastening means by lateral forces can occur, for which the fastening means is not designed.